BE709434A - - Google Patents

Description

  

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 EMI1.1
 

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 EMI2.1
 



  The present 1v.ntion -eat relating to the element. photopolymerisailest On connitt dei '14nt. photÓpolym4ri..blo, comprising a sheet of Povà% àmon%, orPaohablo. We know yes that MAI. ot îlle tMnep6Mn '& ô efehable used as a protein excavation, ow a photopolymerizable layer during the exposure, avoids the deinhibition effect of 1'exysèM on 1. photopolyra4ri.at1on potion.

   Loo sheets of coat 'àPPàéhoblo8 are .14t.i ".' M # where% ouxéb o% oxigina tut trea- tamentally for their .n16vtmtnt, while q.11ÓI are dittoilon to apply his $ to plague pockets of liver between 401, fauààXo % too coating and] this layer 'phoippelyoyiesbict Water insoluble wax couchoo could have been placed!' a comohe used to perform tranotont 4'imaa # o theiQU @ $ but ose coucheu éon% à $ omon% dôéoevànÀ tasouo * 4 in some regardeg Loo 416monte photopolym6n.lb, l .. according to the present invention include, in It order;

   (1) one suppoz-t read case. 4th, an anti-hedge layer, 2) a phtopolYm6r1uèbl colieht. having a weight of 1-90P preferably of 10-50- mgfdà2 a; the dry state comprising (a) at least 6 z 11ë4oor: - ', non-gaseous nylenic containing in the group, Terminal f6niqu.s, having a boiling point greater than 100 at the normal atmospheric pos1on and capable of egmoi-the polymer by polyzeriso.

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 photoinitiated ion, (b) an addition polymerization initiator which can be activated by actinic light, and (c) a macromolecular organic polymer serving as a binder for said ethylenically bonded compound and compatible therewith, and (3) a solid and coherent protective layer, permeable to actinic light,

   these photopolymerizable elements being characterized in that the protective layer has a weight of 2-30 mg / dm2 and is in the form of a homogeneous and non-peelable unsupported film which is substantially impermeable to oxygen, permeable. in water and consisting of at least one macromolecular organic polymer or a mixture of such polymers, which is soluble at 20 C in water or in a mixture of water and an organic solvent miscible with water containing at least 50% by volume of water.



   As macromolecular organic polymers having the characteristics indicated above, there may be mentioned polyvinyl alcohol and its partial esters, ethers and acetals which contain a significant amount of unsubstituted vinyl alcohol units, so as to have the desired solubility in water. As other suitable polymers, mention may be made of polyvinyl acetate hydrolyzed in an amount of 88 to 99%, gelatin, acacia, methyl vinyl ether maleic anhydride copolymers, polyvinyl pyrrolidones, polymers of molecular weight. High water-soluble ethylene oxide having an average molecular weight between 100,000 and 3,000,000 and mixtures of these polymers.



   As suitable photopolymerizable layers and supports for use, there may be mentioned those described in

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 U.S. Patents 2,760,863 and 3,060,026, including carriers bearing the various anti-halo layers and intermediate layers or anchor layers described in these patents. Preferred supports are thin and flexible, while exhibiting a hydrophilic surface. These supports can, for example, be made of steel sheets and grained aluminum sheets.

   Photopolymerizable layers may contain dyes, pigments, fillers, thermal polymerization inhibitors, plasticizers, as well as other ingredients, including particular ingredients of the types described in the aforementioned patents, as well as in the United States patent. U.S. Pat. No. 3,203,805 or the chain transfer agents described in U.S. Patent No. 3,046,127. These latter agents can be found in layer (3).



   As polymer binders which can be used for layer (2), mention may be made of those indicated below and described in United States Patents Nos. 2,760,863 and 3,060,026. Preferred organic polymeric binders are those which have water-soluble acidic or saline groups, for example carboxylic or sulfonic groups.

   The number of these acid groups should not be sufficient to render the polymer soluble in a dilute solution of sodium hydroxide, however the polymer should be soluble in a mixture of an organic solvent, water and a mixture. sufficient amount of alka- to transform the majority of acid groups into salt groups. A particular mixture of solvents formed of iscpropanol and water in a 10/90 ratio and containing 0.1% NaOH can be used at room temperature to remove the exposed parts in elements comprising a combination of certain especially preferred binding materials,

   

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 such as methyl acrylate / methacrylic acid and styrene / itaconic acid copolymers, and an ethylenically linked compound which is preferably insoluble in water.



   The protective layer is applied under. form of an aqueous solution or of a solution in a mixture of water and an organic solvent of the macromolecular organic polymer.



  The obtained layer adheres, after drying, adequately to the photopolymerizable layer and it is so thin that it cannot be mechanically peeled, without support, at one time, from the photopolymerizable layer. When a surfactant with wetting properties is present in the solution used to form the coating, more uniform layers are obtained. The layer is usually very thin, its thickness being about 0.4 to 6.0 microns. This layer can preferably be removed in conventional developer solutions used to form a re-print. lief, after exposure of the phtopolymerizable layer to form an image.

   This last layer is removable in the area comprising an image, while the protective layer can be removed over the entire surface of the treated element.



   As surfactants which can be used, mention may be made of anionic, cationic and nonionic surfactants, such as sodium alkyl sulphates and sulphonates containing 12-18 carbon atoms, such as sodium dodecyl sulphate and sodium octadecyl sulphonate. ; N-acetyl and C-cetyl betaines; alkylaminocarboxylates and dicarboxylates and polyethylene glycols with an average molecular weight of less than 400.



   The developer solution can be used as a cu bath as a spray. Pick up

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 unexposed portions of the photopolymerizable layer can be facilitated by brushing, application of a damp sponge and rubbing, as well as other known methods.



  These treatments help to remove the layer (3) of the relief image.



   The dissolving media used to develop the exposed plaques are aqueous media, that is to say media containing mainly water. Preferred developers also contain an organic solvent and an alkaline material. As suitable organic solvents, isopropanol, butanol, diacetone alcohol, 1-methoxyethanol, 2-ethoxyethanol and 2-n-butoxyethanol can be cited. As suitable alkaline materials, there may be mentioned alkali metal hydroxides, sodium metasilicate, triethanolamine, morpholine and trisodium phosphate. The developer may also contain a wetting agent or a surface tension lowering agent.

   As other ingredients which may be present in the developer solution, there may be mentioned dyes, salts to control the swelling or salts to attack the base metal.



   A preferred developer for the elements exposed according to the present invention to form an image is a 10% by volume isopropanol and 90% by volume water solution containing 0.1-0.3% d. 'sodium hydroxide. Another suitable developer is an aqueous solution of 2-butoxyethanol.



   The support preferably has a hydrophilic surface at the time the photopolymerizable layer is applied.



  Thus, when the plate is exposed and developed to remove the photopolymerizable layer in the unexposed parts, the uncovered areas of the support are desensitized, that is.

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 say that they repel oily or lipophilic ink, while they are receptive to water or aqueous solutions. However, the same end result can be obtained with a support having an initially less hydrophobic, or even hydrophobic, surface, for example with a copper support. In this case, it is necessary to treat the developed plaque with a material such as gum arabic (preferably in the presence of phosphoric acid) which preferably adheres to the surface of the support in the parts. - green (not exposed), to protect them and make them hydrophilic.

   Although gum arabic is the most common treatment material for this use, similar results can also be obtained with materials such as alginic acid, sodium starch glycolate and carboxylethyl cellulose. Even when the support initially has a hydrophilic surface, it is sometimes desirable to treat the developed plaque with gum arabic or an equivalent material.



   The support is preferably thin and flexible, its thickness being between about 0.13 and 0.76 mm.



  Aluminum is commercially available in very different sizes. Aluminum may be untreated (except for the thin oxide layer that forms immediately on its surface when exposed to air) or may have been subjected to surface treatments or coated. coatings providing a hydrophilic surface. The surface can be roughened mechanically, chemically or electrically, to improve the retention of aqueous liquids and also to improve adhesion to the layers to be applied to that surface.



   As other metals suitable for use as supports,

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 mention may be made of tinned steel, stainless acid, aluminum plated steel, unplated steel, galvanized carbon steel and zinc. Plastic films can also be used, for example polyethylene terephthalate films and co-polymer coated films as described in US Pat. No. 2,779,684, US Pat. paper, cardboard, and resin-impregnated or coated paper or cardboard, which may have a hydrophilic surface.



   Preferred photopolymerizable monomers which may be present in layer (2) include substantially water-insoluble materials containing 2 or more terminal ethylenic groups, which are described in US Pat. America n 2,760,863 and 3,060,023.



  Monomers having only one terminal ethylenic group could be used, but the resulting composition would be much less sensitive to actinic light. When chain transfer agents are present in the photopolymerizable layer, in particular polyolefin oxides of the type described in United States Patent No. 3,046,127, glycerol or triethylene glycol diacetate, higher speeds are obtained. This is true both in the case where the agent is originally present in the layer and in the case where it is brought there by migration from a continuous layer.

   Another advantage of the presence of the chain transfer agent in the protective layer coating composition is that the adhesion between the photopolymerizable layer and the protective layer is improved. Triethylene glycol diacetate is

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 the particularly preferred compound, on account of its relatively low vapor pressure which slows down its elimination by evaporation.

   When the chain transfer agent is present, it can be used in amounts up to 50%.
 EMI9.1
 of the monomer containing ethylene
Preferred addition polymerization initiators, which can be activated by actinic light and are heat insensitive up to 185 ° C, consist of the substituted and unsubstituted polycyclic quinones.



  A large number of such quinones which can be used as polymerization initiators are described in US Pat. No. 2,951,758. Addition polymerization inhibitors may be present in the photopolymerizable layers in amounts up to 2% by weight of the layer.



   Components (a) and (c) are present in the photopolymerizable layer in amounts between 10 and 60 parts and 90 to 40 parts by weight respectively, and component (b) should be present in an amount of 0.5 to 10% in weight
 EMI9.2
 of component (a), the ethylenically bonded compound.



   The photopolymerizable elements according to the present invention can be used to obtain various images or patterns. They are especially suitable for obtaining relief prints. One advantage of these elements is the improved contrast and speed. Printing plates obtained from these elements can be used for exceptionally long times in printing presses. Thin protective coatings have many advantages over known tear-off protective sheets. They are thinner than these sheets, while being of good uniformity.

   Moreover, because of their

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   uniform adhesion, they are more effective as layers impermeable to oxygen. -
The invention is further illustrated by the following examples, without however being limited thereto. In these examples, percentages and parts are by weight, unless otherwise indicated.



   EXAMPLE I.



   A grained aluminum plate, the surface of which was treated with an aqueous solution of sodium silicate, was covered with a layer of a solution of methyl ethyl ketone and isopropanol (3: 1) containing 20% of solids of the following composition:
Binder of polyMethyl methacrylate / methacrylic acid / (molar ratio 90 / la) * 53.8% Pentaerythritol triacrylate containing 44.1%
0.4% p-methoxyphenol as thermal inhibitor
Tert. -butylanthraquinone 2.0%
Ethyl violet dye (CI Basic Violet 4) 0.1%
Approximate dry layer weight 87 mg / dm2
After drying, the plate was heated to 130 ° C for 1 minute and cooled.

   The plate was covered with a layer of a 3% aqueous solution of polyvinyl alcohol (average viscosity, 99% saponified) containing 2% of a polyoxyethylene surfactant of the formula:
 EMI10.1
 The weight of the phoopolymerizable material layer was 86 mg / dm2. The weight of the polyvinyl alcohol layer was 12 mg / dm2. x Intrinsic viscosity - 0.094 with methyl ethyl ketone as solvent.

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   The plate was exposed for 30 seconds through a negative (Lithography Technical Foundation 21 grdinz exposure wedge) in a vacuum frame, using a carbon arc lamp placed at a distance 17 '' and operating at 45-50 amps and 1200 watts. There was thus obtained an element in which the first seven steps were sufficiently polymerized to withstand removal during subsequent development.



   The plate was developed by washing away the unexposed parts of the coating, using a developer having the following composition: 99% isopropyl alcohol 10% (by volume) Sodium hydroxide 0.1 % Water '. ,; 89.9% (by, volume)
The plate was covered with ec developer allowed to soak therein for 30 seconds. All the protective layer, as well as the unexposed parts of the light-curing layer were removed with a sponge. The developed plaque was then rinsed with water and dried.



  The plate exhibited good ink and water characteristics, that is, the exposed photopolymerized portions readily accepted lipophilic inks, while the carrier portions, whose unexposed photopolymerizable material had been removed, readily accepted water. The plate has been successfully used in an offset type printing press using black printing ink and aqueous solution.



   A plate similar to that described above was covered with a commercial gum-based etching composition containing gum arabic, which was applied.

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 after rinsing, but before drying. The plate was then rubbed until dry, after which it was inked and used in a press or duplicator. The results obtained were the same as described above, except that the plate was insensitive to fingerprints in the non-printing parts.



   The procedure described above was repeated, except that a 1: 1 mixture of methyl ethyl ketone and isopropanol was used as solvent, and the coating was cured for 2 minutes at 15 ° C. and that 88% saponified medium viscosity polyvinyl alcohol was used for the protective layer. After exposure, processing and drying, the plate was post-exposed for 5 minutes in a vacuum exposure frame, using the same light source as for the initial exposure. This plate was used to obtain 246,000 prints. At the end of this test, no visible signs of wear were observed and no special precautions had to be taken with this plate during the tests.

   A similar plate treated in the same manner was used to print an abrasive pastel ink. After 103,000 impressions, there was no sign of wear.



   Comparable results were obtained using the procedure and compositions described in the present example, but making the following changes:.



  1. The polymeric binder present in the photopolymerizable composition was poly (styrene-90 / itaconic acid-10) or poly (methyl methacrylate-95 / itaconic acid-5).



   2. The protective layer was a 3% aqueous gelatin solution (surfactant present in the same amount) and the weight of the dry layer was 13 mg / dm2.

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  3. The exposed plate was treated with water to remove only the protective layer of polyvinyl alcohol. Diethylene glycol mono-n-butyl ether was used to develop the unexposed portions of the plaque. A particularly sharp and clean image was obtained.



    4. The photopolymerizable material solution consisted of ethylene glycol monoethyl ether or trichlorethylene (20% solids).



   EXAMPLE II.



   Pclened and untreated aluminum foil was cleaned in a degreaser using a vapor-phase degreasing solvent, after which it was treated for -2 minutes in a composition containing chromium, to obtain a solid surface. chromium oxide. The plate was covered with a solution having the following composition: Binder from Example 1 13.4% by weight Pentaerythritol triacrylate 11.0% Tert.-butylanthraquinone 0.6% Methyl ethyl ketone 75.0%
The resulting layer was dried at 110 ° C. and cured for 1 minute at 130 ° C. A protective layer of polyvinyl alcohol was then applied as described in Example I.

   A printing plate was prepared by exposure through a negative, as in Example I, developing in 0.1% NaOH in a 3: 1 (by volume) mixture of. water and isopropanol, by rinsing with water, by treatment with a sponge impregnated with a solution containing
10% zirconium oxychloride and 20% glycerol in water, by rinsing with water, and by rubbing with a composition containing gum arabic. The plate obtained gave complete satisfaction in a printing press.

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   EXAMPLE III.



   Steel plates approximately 0.3 mm thick electrically coated with a zinc plating were treated, by two different methods, to obtain hydrophilic surfaces. These plates were coated with a composition similar to that of Example I, except that methyl ethyl ketone was used as the solvent and the solids content was 18%. The resulting layer was dried at 100 ° C and cured at 130 ° C for 2 minutes, after which a protective layer of polyvinyl alcohol was applied as described in Example I. The plates were exposed as in 1. Example I and developed in a 4: 1 (by volume) mixture of water and isopropanol containing 1% sodium metasilicate. The resulting plates performed satisfactorily in a printing press.

   These plates exhibited good ink and water retaining characteristics and had no tendency to foam.



   EXAMPLE IV.



   The procedure was as in Example I, except that the exposed plaques were treated in the following developer solutions, A to H. The plaques developed in each of these solutions gave results substantially corresponding to those obtained in Example I.

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   DEVELOPER Parts / 100 in water (by volume)
 EMI15.1
 AC DEFGH Isopropanol 20 Diacetone alcohol 12 2-ethoxyethanol 5.0 2-n-butoxyethan ol 2, 0 f, 0 4 4 2.8 Sodium hydroxide 0.3 0.2 Sodium metasilicate 1 1 Triethanolamine 3 Morpholine 5 Phosphate trisodium 0.1 0.1 C8H1- / \ -0- (CH2CH20) 9-11 0.1 0.02 0.1 Sodium alkanesulphonate 0.7 to 18 carbon atoms, surfactant
EXAMPLE V.



   The following composition was prepared as a 20% solution in a 1: 1 mixture of methyl ethyl ketone and isopropanol: Binder of Example 1 53.8% Triethylene glycol diacrylate 44.1% Violet dye ethylu (CI basic violet 4) 0.1% Tert. -butylanthraquinone 2.0%
This composition was applied as a layer, as described in Example I, after which this layer was covered with a protective layer of a 3% aqueous alcohol solution. polyvinyl (saponified 86-89%, viscosity 19-25 centipoise in 4% aqueous solution at 20 C)

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 containing 2% (based on the weight of polyvinyl alcohol) of polyoxyethylene surfactant of Example I.

   One sample of the plate was exposed as described in Example I through a 21-step LTF exposure wedge, while another sample of the plate was exposed through a special test negative used. to appreciate the ability of the plate to faithfully reproduce halftone lines. The two samples were developed in a solution having the following composition:
 EMI16.1
 817 O 229Ô10 '0.1% Trisodium phosphate 0.1% Sodium hydroxide 0.2% 2-n-butoxyethanol 2.0% Water 97.0.



   The plate exhibited good ink and water differentiating qualities, good adhesion to the substrate, good reproduction quality of halftone lines, and satisfactory prints were obtained with this plate. plate on a classic printing machine. Similar results were obtained with a plate covered with a layer of a composition, of which the monomer was constituted by trimethylolpropane triacrylate. The use of 9,10-phenanthrenequinone had no effect on the results: However, when the protective layer of polyvinyl alcohol was not used, a decrease of a factor of 8 in the photographic speed was recorded.



   EXAMPLE VI.



   The composition of Example I, in the form of a solution of
20% solids in a 1: 1 mixture of methyl ethyl and isopropanol ketone, was applied as a layer on the plates

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 of grained aluminum of Example I, to form a number of plates which were covered with a layer obtained with aqueous solutions, -, various waterproofing agents vis-à-vis the oxygen, the dry layers having a weight of about 12 mg / dm2.

   It was found that a plate without an oxygen barrier layer required an exposure time 8 times greater than that required for an otherwise identical plate covered with a layer of polyvinyl alcohol. to achieve the same degree of polymerization, using a 21-step exposure corner from the Lithographie Technical Foundation. This relatively large difference in exposure time was used to select materials with low oxygen permeability. Of the various protective layers that were applied to the plates, two layers gave almost identical plates to the polyvinyl alcohol coated plate of Example I.

   These two layers were made up of: A - Gum arabicue (applied as a 12% aqueous solution) B - Poly (methyl vinyl ether / maleic anhydride), 1: 1 copolymer having a specific viscosity of 0.1- 0.5 ,, determined on a solution of 1 gram of copolymer in
100 ml of methyl ethyl ketone at 25 ° C. (3% aqueous solution).



   Another interesting layer has been obtained by using a 5% aqueous solution of a water soluble polymer of high molecular weight polyoxyethylene having a viscosity of 225 to 375 centipoise at 25 C.



   EXAMPLE VII.



   Aluminum foils of the type described in Example I were coated with thin layers having the following compositions:

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 EMI18.1
 
<tb> layer <SEP> A <SEP> B <SEP> C
<tb>
<tb> Triacrylate <SEP> of <SEP> pentaerythritol <SEP> 15 <SEP> g <SEP> 10 <SEP> g <SEP> 30 <SEP> g
<tb> thermal <SEP> inhibited <SEP> by <SEP> 0.2% <SEP> of
<tb>
 
 EMI18.2
 p-xethoxyphé nol
 EMI18.3
 
<tb> Poly (<SEP> methyl methacrylate <SEP>) <SEP> 12.5
<tb> Poly (<SEP> vinyl acetate <SEP>) 2 <SEP> 12.5
<tb>
<tb> Polystyrene '<SEP> 10
<tb>
 
 EMI18.4
 t-3atylanth = aquinone 0.3 0.3 0.3
 EMI18.5
 
<tb> Phenanthrenequinone <SEP> 0.16 <SEP> 0.16 <SEP> 0.16
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Violet <SEP> ethyl <SEP> (CI <SEP> violet
<tb>
<tb>
<tb>
<tb> basic <SEP> 4) <SEP>.

   <SEP> 0.04 <SEP> 0.04 <SEP> 0.04
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Isopropanol <SEP> 88 <SEP> 88
<tb>
<tb>
<tb>
<tb> Added <SEP> up to <SEP> a <SEP> weight <SEP> total <SEP>
<tb>
<tb>
<tb> of <SEP> nethyl <SEP> ethyl <SEP> ketone <SEP> 200 <SEP> 200
<tb>
<tb>
<tb> of <SEP> toluene <SEP> 200
<tb>
   Low molecular weight, inherent viscosity; 0.20.



  Mol weight. medium = 45,000; visc. of 86 g of resin in 1000 ml of benzene solution determined at 20 C using an Ostwald-Cannon-Fenske viscometer = 6 to 8 cps.



  Specific gravity: 1.05-1.07 (ASTM D792-50 method); thermal expansion index: 1.59 (ASTM D542-50 method); coef-
 EMI18.6
 6-8 x 10 em / cani C (ASTB method D696-44).



   The three plates were covered with a layer of a polyvinyl alcohol solution of the type described in Example I, after which they were exposed for 60 seconds, using the apparatus described in Example I. The plates were developed as described in Example IV, using developer composition D. All three plates showed good differentiation in ink and water, as well as in water. good adhesion to the support.



  These plates gave prints faithfully reproducing halftone lines.

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   EXAMPLE VIII.



   Aluminum supports analogous to those of Example I were coated with a layer having the following composition, to form three photopolymerizable plates.



  Poly-5-vinylpyridine 5.4 g Pentaerythritol triacrylate 4.4 g Tert.-butylanthraquinone 0.2 g Ethyl violet (CI Violet-Basic 4) 0.01 g Methyl ethyl ketone / isopropyl alcohol (1: 1) 73 g
All three plates were coated with a protective layer of a polyvinyl alcohol solution as in Example I, exposed through a negative and each developed with one of the following solutions: 1. Isopropyl alcohol (99 %) - after prior removal of the protective layer of polyvinyl alcohol using a sponge soaked in water.



  2. Acetic acid, 0.1% solution in water.



  3. Attack solution consisting of:
Calcium chloride 41 Bé 1000 ml
Zinc chloride 380 g
Iron perchloride 51 Bé 285 ml
Hydrochloric acid 37-38.5% 114 ml
Cupric chloride (CuCl2-2H2O) 27 g
The plates were dried, post-exposed for 5 minutes and treated with a 14 Bé solution of gum arabic containing 1% sodium metasilicate. These three plates exhibited good differentiating qualities with respect to ink and water. Good printed copies could be obtained when using these plates on a conventional printing press.

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   EXAMPLE IX.



    The photopolymerizable solution of Example I, without the ethyl vblate dye, was neutralized with sodium hydroxide, using phenolphthalein as an indicator. The solution was applied, as a layer, on a grained aluminum support, to which was then applied a layer of a solution of polyvinyl alcohol as described in Example I.

   With exposure Through a negative, the plate was desloped with the aid of the following solution containing no alkaline material:
5ml of 2-n-butoxyethanol
 EMI20.1
 1 ml of surfactant pc: -. Yéthl, enique c $ Hl¯ l ¯ō (, zo99l0
94 ml of water Plque gaté treated with a gum composition (946 cm3 of gum arabic at 14 Bé + 29.57 cm3 of
H3PO4). After s @@ age, the plate was postexposed for 5 minutes in a frame vacuumed as described in Example I. Using conventional black printing ink, was obtained. , with this plate, 2000 impressions of good quality, without appreciable wear of the plate.



   EXAMPLE X.



    Four aluminum supports, treated cotame described in Example I, were provided with an ati-halo protective layer, using a yellow dye (absorbing ultraviolet light and blue light) corresponding to the following formula:
 EMI20.2
 

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1 g of the dye was dissolved in 100 ml of a mixture.
10/90 of water and ethylene glycol monoethyl ether. The solution was applied as a layer on plate 1 and dried by evaporation at room temperature.



   Plate 2 received an anti-halo layer formed from a solution prepared by dissolving 1 part of the yellow dye and 100 parts of the monomer (pentaerythritol triacrylate) in monoethyl ether of ethylene glycol to obtain a solution. - tion containing 5 g of solids per 100 ml.



   Plate # 3 received an anti-halo layer analogous to that of Plate # 2, except that the monomeric pentaerythritol triacrylate was replaced by an identical amount of the polymethyl methacrylate / acid copolymer binder. methacrylic of Example I.



   Plate # 4 received an anti-halo layer obtained using a solution prepared by dissolving 1 part of the yellow dye and 100 parts (dry) of a photopolymer composition further defined as "Composition # 1".



   Ethylene glycol monoethyl ether was used as a solvent; the solution contained, per 100 ml of volume, 5 g of solids.



   Another treated aluminum plate, namely plate 5, received an anti-halo layer obtained by using an aqueous solution containing 0.025 g per liter of an ultraviolet light absorbing material based on substituted benzophenone. soluble in water, exhibiting an absorption peak at. 284 millimicrons,
The exact weight of the anti-halo layers has not been determined, but for layer 1, the optical density of reflection through a blue filter was about 0.27, or

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 0.04 higher than the density recorded for the aluminum substrate, before application of the anti-halo layer.

   Plates 2, 3 and 4 carried anti-halo layers having somewhat higher optical densities. No density could be discerned for the anti-halo layer of Plate 5, since the dye used was an ultraviolet light absorbing dye.
 EMI22.1
 



  The following photipolymerizable compositions were prepared:
 EMI22.2
 
<tb> Composition <SEP> Composition
<tb>
 
 EMI22.3
 ContDosants n 1 -n 2 Pentaerythritol trsacrylate '66 g 576 g L4-a, it from example 1 3t> ',, g 621r g
 EMI22.4
 
<tb>
<tb>
 
 EMI22.5
 Po.r (methyl methacrylate) of Example VII z z t'Bmylanthraquinone 8.6 $ g 944 g Penanthrenecuinone 3.94 g '7e2O g
 EMI22.6
 
<tb> Blue <SEP> oil <SEP> A <SEP> (OI <SEP> Blue <SEP> solvent <SEP> 36) <SEP> 2,0 <SEP> g <SEP> @ 6
<tb>
 
 EMI22.7
 Monoethyl ether ethylene glycol. ' col, to form a 35% solution of about 37% solid solids;

   
Plates 2, 3 and 4 provided with the anti-halo layers described above were covered with a layer of the com-
 EMI22.8
 position n 1, to obtain photopolymerizable layers having, when dry, a weight of about 30 mg / dm2. The plates were then covered with a protective layer formed from a 6% by weight aqueous solution of polyvinyl alcohol (medium viscosity, 88% saponified) containing 2% (based on the dry weight of the alcohol. polyvinyl) of a polyoxyethylene surfactant of forrnzl:
 EMI22.9
 

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Plates 1 and 5 were covered with a layer of composition 2, so as to form photopolymerizable layers having, in the dry state, a weight of about 26 mg / dm2.

   To form the layer on Plate 5, the oil blue dye was replaced with an identical amount of Fuchsin dye (CI Violet Basic 14). The plates were covered with a protective layer of a solution of the polyvinyl alcohol and the surfactant described above, but containing (instead of water as the only solvent) approximately 9% ethanol and 9% ethylene glycol monoethyl ether.



  The polyvinyl alcohol solution was applied to form layers constituting very effective oxygen barriers, these layers having, in the dry state, a thickness of about 0.0008 mm.



   All five plates were tested as described in Example I. Substantially similar results were obtained except that the images were sharper, thanks to the anti-halo colorants.



   Similar results have also been obtained using other dyes or ultraviolet light absorbing agents, instead of those described above. Anti-halo dyes should be chosen according to the length of the film. wave of actinic light of exposure which initiates the polymerization: .on. Since this initiation usually takes place in the ultra-violet or blue regions of the spectrum, ultra-violet light absorbing materials and yellow dyes are particularly effective.



   In plates 1 to 4 the anti-halo yellow dye in combination with the oil blue dye present in the light-curing layer gave a pleasant green tint.

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 to the exposed parts of the plate. This color contrasted sharply with the surface of the aluminum where the photopolymerizable material and the dye were removed by development in the unexposed parts. In a similar plate, the oil blue dye was replaced with a similar amount of Victoria Green dye (CI Green Basic 4) which also gave a pleasing hue, in combination with a yellow anti-halo dye.



   EXAMPLE XI.



   The following photopolymerizable coating compositions were prepared:
 EMI24.1
 
<tb> COMPOSITION <SEP> (in <SEP> grams)
<tb>
 
 EMI24.2
 Components N "1 11 2 '. N02 3, Nl: D N-, 5 p uG N O 3' N G 7 N08
 EMI24.3
 
<tb> Tricarylate <SEP> from <SEP> penta-
<tb> erythritol <SEP> 576 <SEP> 406 <SEP> 9.5 <SEP> 9.5 <SEP> 9.5 <SEP> 9.5 <SEP> 9.5 <SEP> 9.5
<tb>
<tb> Trietlylene <SEP> diacetate <SEP>
<tb> glycol <SEP> 128 <SEP> 3.0 <SEP> 3.0 <SEP> 3.0 <SEP> 3.0
<tb>
 
 EMI24.4
 Binder of 1 exera on 1 624 624 lutz, 7 14.7 14.7 14, "lu, 7 14.7
 EMI24.5
 
<tb> Ether <SEP> methyl <SEP> from
<tb>
 
 EMI24.6
 be nzc: ne z4 o, 22 t-bu;

   laahraquinone 9.4 9.4 0.22 0.22 Phpn.nthrenequinone 7 ,? 7.2 0.17 0.17 0.17 0.17 2-.thylanthraquinone 0.4 0.22
 EMI24.7
 
<tb> dye <SEP> blue <SEP> 'acid
<tb>
<tb>
<tb> 102 <SEP> CI <SEP> 16 <SEP> 16 <SEP> 0.3 <SEP> 0.3 <SEP> 0.3 <SEP> 0.3 <SEP> 0.3 <SEP> 0 , 3
<tb>
<tb>
<tb>
<tb>
<tb> Polyethylene <SEP> glycol,
<tb>
<tb>
<tb>
<tb> weight <SEP> mol. <SEP> - <SEP> 300 <SEP> 3.0
<tb>
<tb>
<tb>
<tb>
<tb> Poly <SEP> (sami <SEP> acid <SEP> ester
<tb>
<tb>
<tb>
<tb> succinic <SEP> from <SEP> ethy-
<tb>
<tb>
<tb> lene <SEP> glcyolà <SEP> weight <SEP> mol.

   <SEP> 3.0
<tb>
 
 EMI24.8
 350 'Y P * 3.0
 EMI24.9
 
<tb> Monoethyl ether <SEP> <SEP> from
<tb> ethylene <SEP> glycol <SEP> 20 <SEP> 20 <SEP> 20 <SEP> 20 <SEP> 20 <SEP> 20
<tb>
<tb> Monoethyl ether <SEP> <SEP> from
<tb> ethylene <SEP> glycol <SEP> up to <SEP> a <SEP> total <SEP> weight <SEP> of <SEP> 3500 <SEP> 3500
<tb>
<tb> Xethyl <SEP> ethyl <SEP> ketone
<tb> up to <SEP> a <SEP> weight <SEP> total <SEP> of <SEP> 180 <SEP> 180 <SEP> 180 <SEP> 180 <SEP> 180 <SEP> 180
<tb>
 

 <Desc / Clms Page number 25>

 
The aforementioned compositions were applied in the form of layers weighing 40 mg / dm2, on non-silicate aluminum supports, grained by brushing, with a thickness of 0.3 mm.

   A protective layer of polyvinyl alcohol was then applied as described for plates 2, 3 and 4 in Example X, so as to obtain finished plates which were numbered or marked with the number of the coating composition. used. The plates were all exposed as described in Example I and processed as described in Example IV B.



   Plate a 1, i.e. the control plate, gave an image substantially matching that of the plate of Example I. All other plates gave roughly equivalent results, except that the speed or light sensitivity d 'exposure was twice as large. This increased sensitivity has been attributed to the chain transfer agent consisting of triethylene glycol diacetate in plates 2 and 5 to 8, by polyethylene glycol in plate 3 and by poly (semi-ester d ethylene glycol succinic acid) in plate 4. The various initiators and combinations of initiators gave equivalent results.

 <Desc / Clms Page number 26>

 



  EXAMPLE XII.
 EMI26.1
 
<tb> Composition <SEP> (in <SEP> grams)
<tb>
 
 EMI26.2
 Constituents 1V 1 N 2 N03 N i
 EMI26.3
 
<tb> Triacrylate <SEP> of <SEP> penta-
<tb> erythritol <SEP> 9.5 <SEP> 9.5 <SEP> 9.5 <SEP> 9.5
<tb>
<tb> Binder <SEP> of <SEP> example <SEP> 1 <SEP> 14.7 <SEP> 14.7 <SEP> 14.7 <SEP> 14.7
<tb>
<tb> Blue <SEP> of <SEP> methylene <SEP> (CI
<tb> Blue <SEP> Basic <SEP> 9) <SEP> 0.2 <SEP> 0.2 <SEP> 0.2 <SEP> 0.2
<tb>
<tb> Triethanolamine <SEP> 1.5 <SEP> 1.5
<tb>
<tb> 5,5-dimethyl-1,3cyclohexanedione <SEP> 0.35 <SEP> 0.35
<tb>
<tb> 5-butylanthraquincne <SEP> 0.22 <SEP> 0.22
<tb>
<tb> Phenanthrenequinone <SEP> 0.17 <SEP> 0.17
<tb>
<tb> Triethylene <SEP> diacetate <SEP>
<tb> glycol <SEP> 1.5 <SEP> 1.5 <SEP> 3.0 <SEP> 3,

  0
<tb>
<tb> Monoethyl ether <SEP>
<tb> ethylene <SEP> glycol <SEP> 20 <SEP> 20 <SEP> 20 <SEP> 20
<tb>
<tb> Met <SEP> @yl <SEP> ethyl <SEP> ketone
<tb> up to <SEP> weight <SEP> total <SEP> of <SEP> 180 <SEP> 180 <SEP> 180 <SEP> 180
<tb>
 
These compositions were applied to metal supports which were then provided with a protective layer of polyvinyl alcohol. The resulting plates were exposed and processed as described in Example XI. All the compositions contained a dye-redox system as a photoinitiator. Compositions Nos. 2 and 4 additionally contained a combination of quinone-type photoinitiators and therefore had a speed approximately equal to twice that of Compositions Nos. 1 and 3.

   The four coating layers had the advantage of giving a visible image immediately after exposure by the action of methylene blue. Another plate was prepared having a photopolymerizable layer having a composition analogous to composition 1, except that the methylene blue was replaced.

 <Desc / Clms Page number 27>

 with an identical amount of another photoreducible dye, namely erythrosine. The quality and speed of the plate were the same, but the erythrosine was unable to produce a visible image.



   EXAMPLE XIII.



   A plate A to serve as a control, substantially identical to plate 2 of Example XI, was prepared.



  A plate B was also prepared which differed from plate A only in that the protective layer of polyvinyl alcohol was replaced by a protective layer of polyvinyl pyrrolidone having an average molecular weight of 40,000. A plate C was also prepared provided with a protective layer of polyvinyl pyrrolidone, this plate however comprising a much coarser-grained aluminum support than that used in the other plates. In this case, the aluminum support was roughened by sandblasting, so as to have a roughness value of 10 seconds, while the roughness value of the aluminum support used for plate A was. of 218 seconds, these values being determined by the method described by J.

   Bekk, "Apparatus for Mea $ uring the Smoothness of Paper Surfaces", June 30, 1932, Paper Trade J. A plate D having a rough surface similar to that of plate C and provided with a protective alcohol layer was prepared. polyvinyl similar to that * of plate A.

   The four plates were exposed for 3 minutes through a continuous shade negative having a 21-step V-exposure wedge. Exposure and development will be performed as described in Fig. example VII. Prints were made with each of the four plates and, as shown in the following table, the combination of backing to surface

 <Desc / Clms Page number 28>

 the coarser and the protective layer of polyvinyl pyrrolidone gave the greatest number of steps with different print densities. Furthermore, the image of the continuous-tint negative was reproduced most faithfully by plate C.
 EMI28.1
 
<tb>



  Layer <SEP> Number <SEP> of <SEP> steps <SEP> printed
<tb>
<tb> Plate- <SEP> Sunport <SEP> protective <SEP> mes <SEP> clearly visible <SEP>
<tb>
<tb>
<tb> A <SEP> (witness) <SEP> current <SEP> polyvinyl alcohol <SEP> <SEP> 3
<tb>
<tb>
<tb> B <SEP> current <SEP> polyvinyl <SEP> pyrrolidone <SEP> 8
<tb>
<tb>
<tb>
<tb> C <SEP> coarse <SEP> polyvinyl <SEP> pyrrolidone <SEP> 10
<tb>
<tb>
<tb>
<tb> D <SEP> coarse <SEP> polyvinyl alcohol <SEP> <SEP> 5
<tb>
 
A protective layer of polyvinyl pyrrolidone has advantages over a protective layer of polyvinyl alcohol, for preparing a plate from a continuous shade negative, because the layer of polyvinyl pyrrolidone is not as impermeable to oxygen.

   Oxygen impermeability is preferable for printing from a halftone negative because, with the greater oxygen impermeability inhibiting polymerization, the coated plate a protective layer of polyvinyl alcohol is more photosensitive.



   Another plate was prepared analogous to the No. 2 plate of Example XI, except that the polyvinyl alcohol half of the protective layer was replaced with polyvinyl pyrrolidone of a. average molecular weight of 40,000.



   This plate was substantially equivalent to plate # 2 except that the adhesion between the light-curing layer and the protective layer was better. Even better adhesion was obtained by adding 2% triethylene glycol diacetate to the composition of the protective layer.

 <Desc / Clms Page number 29>

 



   Yet another plate analogous to that described in Example XI was prepared, using composition 2 to form the photopolymerizable layer. However, the protective layer was replaced by a layer obtained using a layer. aqueous solution containing 3% polyvinyl alcohol (average viscosity, saponified 99%), 2% 4,4'-diazidostilbene-
Sodium 2,2'-disulphonate and 2% (based on the weight of dry polyvinyl alcohol) of a polyoxyethylenic surfactant of the formula:

   
 EMI29.1
 
After exposure to image as described in Example XI, the yellow diazide was processed to form a clear, laughable image useful for checking plaque prior to processing as described in this example. A satisfactory printing plate was obtained. - EXAMPLE XIV.



   Results similar to those obtained in Example IX can be obtained by using, instead of the photopolymer solution of Example I, the particular polymers containing acid groups which are described in Example I or by using other particular organic polymers containing acidic groups, especially the addition copolymers described in US Pat. No. 2,893,868. The polymers described in this patent contain, for example, free acid side groups, such as sulfonic, carboxylic and phosphoric groups.

   Before esterification, these polymers can be neutralized with a base, for example with an alkali metal hydroxide, such as sodium or potassium hydroxide, or with the aid of a corresponding carbonate or ammonia or alternatively a substituted ammonium base,

 <Desc / Clms Page number 30>

 
 EMI30.1
 such as t6tramethylEirriionium hydroxide and hydroxide of -, et.-a6, hy: .ai., r, cnium, or alternatively with the aid of an organic amine, such as ethanolarin, ethylene diàn, ine, la ài & t, qylènetriu; <, ine, 2-amino-2-hydroxymethyl-1,3-propan-diol, α, 3-diair, inopropanol-2 and morpholine, ae so that the acid groups free are transformed into salt groups.

   The layers obtained have the advantage that they can be removed in the aqueous solvents of Example IX or other alkali-free solvents.

 

Claims (1)

CLAIMS. EMI31.1 the now light-curing puller, from Itora dre, (1) a support, EMI31.2 (t) utti tou0he phoÔopolp4Pioobl * having a weight of 1-90 1u / Ôml 196% 4 Me and comprising (a) at least one non-gttseous dthyldniqueo liliteon compound coRMMM wu 9% oing two groupµ ioull6nies toriiiin4ump ay011% a dge point greater than at00C at i6 normal oun8yhOPiquo pros- sion and, capable of foptMer a po. lymire by addition polymerization photchoyce (b) an activated addition polymerization initiator EMI31.3 by the 14th morning f and (e) a binder maormoldeuloirop a solid protective layer paniablo the lumi4ro * oçti- nique, characterized in that the protective layer has a weight of 2-30 EMI31.4 nl / 4Nù and and; % howogéno, non orrbohoblo gous Mt6 of non-oupperbdef film Donsiblekiont tmpomdable to Itoxygénop pomréble 4 water and consisting of eu monk a polymer oepreiquo chickweed & Ol'OU18àP0 so.ir'1,. = rtï r 2090P dsnb i'b "1 0Y "?" Including a 441enr "e of water and a misotble organic solvent 4 containing lm theine 5E $ by volume of water, 2. The following is claimed in claim 1, wherein the polymeric binder contains water soluble salt groups. EMI31.5 3. Ilérasss according to claim A, 0 cibne which the support is metallic. EMI31.6 4. "7glemonP * according to claim 3, wherein the tupport is a 3.wainium. µ. 2ren follow one or otter of the preceding claims% ions,%, characterized in that the support comprises an anti-kalo layer. <Desc / Clms Page number 32> 6. - Extinct according to one or the other of the claims EMI32.1 like previous ones, in which Io compo # d at 1.110ns'thyl'ni. almost insoluble in 1 q water and 1 oouche contains in tgenro tensio-actift 7. "gliment s! t'6 l'uhé w Itautre des r.v.n4o .. % ion precid4nteo $ in which a: Ln1t1attur of the typo quinon. polycyclic which can be activated by the 1u & àir * lot1h1qu. * t thermally 1n.ott! , urt of 185110 and MiM is loaned in the ctuch. phiyMt <tbi $ <8.- 316men # suit.fit 1'utsl or 1tau, ttrt de. rovondioations prddontooo where the polymeric binder is a 4opolymer. methyl methacrylate. and methacrylic acid or a copolymer of styrene and resolves ttlconique. 9.- il'mon% according to one or other of the preceding v <mdica "tions, in which the constituents (a) and la) are present in respective proportions of 10 to 60 and 90 to 40% in weight. 10. - Next item, either of the preceding% claims, in which the protective layer (3) contains polyvinyl alcohol, 88-99% hydrolyzed polyvinyl acetate. gelatin, gum arabic, high molecular weight methyl vinyl ether / maleic anhydride copolymer, ethylene oxide polymer, polyvinyl pyrrolidone and, optionally, triethylene glycol diacetate and / or a surfactant of formula: EMI32.2 11.- Element. light-curing comp. in .nt in the order: <Desc / Clms Page number 33> (1) Aluminum backing sheet with a thickness of 0.13 to 0.76 mm, (2) a photopolymerizable layer having a weight of 1-90 mg / dm2 and comprising EMI33.1 (a) tril: pentadrythritol rylate (b) an addition polymerization initiator of the polycyclic quinone type EMI33.2 (c) a 6opo2.yMe m4thylt / methacrylic acid methactylate, fia (d) diaoea% e triethylene glycol # and an adherent protective layer containing polyvinyl alcohol, polyvinyl pyrrolidone, diacetate. EMI33.3 triethylene and an active agent of the formula! EMI33.4 12.- Process consisting in exposing to actinic light, so as to form an image, a photopolymerizable element according to any one of claims 1 to 10,. so as to form an insoluble polymer emage in the by. exposed parts of the diaper and remove the protective layer with the unexposed parts of the diaper, using an aqueous solvent. 13. A method according to claim 12, characterized in that the aqueous solvent is a mixture of 2-n-butoxyethanol, trisodium phosphate and water, this mixture containing a surfactant. 14. A method according to either of claims 12 and 13, wherein the protective layer is removed before non-exposed portions are removed.